Centrifugal pump with adjustable capacity



Feb. 9, 1965 H. HORNSCHUCH 3,163,370

CENTRIFUGAL PUMP WITH ADJUSTABLE CAPACITY Filed Dec. 12, 1962 2 Sheets-Sheet 1 FIG;

FIG. 4

INVENTOR.

HAN/V5 HORNSCHUCH ATTORNEY Feb. 9, 1965 H. HQRNSCHUCH CENTRIFUGAL PUMP WITH ADJUSTABLE CAPACITY 2 Sheets-Sheet 2 Filed Dec. 12

FLUID SUPPLY MEANS FIG. 2

INVENTOR.

AT TO R N EY HAN/V5 HO/P/VSCHUGH United States Patent This invention relates to pumps and more particularly to a device for varying the capacity of the pump.

Heretofore it has been known in the pump art, that in order to vary the output capacity of a pump a portion of the output pressure may be bled-off by means of mechanical linkage devices or, valves, thereby reducing the output capacity of the pump.

A similar device is disclosed in US. Patent 2,874,642 issued February 24, 1959, to Frank R. Forrest wherein a gear mechanism is used to vary the size of a bleeder passage thereby varying the output of the pump. It is obvious to those skilled in the art that when such a device is used particularly for the purpose of pumping a material such as contaminated fluid or pulpy fluid, the sludge which is present in the pumped liquid will clog and stick to the linkages and gears which operate the control mechanism and thereby cause the mechanism to become inoperative.

In the art'"of pumps for moving abrasive fluids, diaphragms or inflatable and deflatable tire like diaphragms have been used to prevent the abrasive material being pumped from entering into the mechanism of the pump itself thereby preventing wear within the pump. The use of such diaphragms is clearly seen in the US; Patent 2,778,315 issued January 22, 1957 to R. R. Crookston et al. wherein hydraulic fluid is disposed within the piston chambers and is fed to a system of diaphragms and valve mechanisms to inflate and deflate the diaphragms according to the movement of the piston. The hydraulic fluid is either moved into the tire-like diaphragm or removed from the tire-like diaphragm by the action of the various pistons associated with the pump. This device, however, is more or less a blocking mechanism rather than a controlling mechanism and its use in connection with a control mechanism (for controlling the capacity of a pump) would be highly undesirable in its present state as disclosed in this patent.

It is the general object of the present invention to avoid and overcome the foregoing and other difliculties of and objections to prior art practices by the provision of a well constructed pump.

Another object of the present invention is to vary the capacity of a pump without changing the speed of the prime mover.

Yet another object of this invention is to vary the capacity of a pump without using mechanical linkages or gears.

Still another object of this invention is to eliminate linkages and gears which are susceptible to a clogging and sticking because of the nature of the material being pumped.

A further object of this invention is to provide an economical method of varying the capacity of a pump without introducing mechanical connections which are susceptible to breakdowns.

The aforesaid objects of the present invention, and other objects which will become apparent as the descrip tion proceeds, are achieved by providing a control device for varying the fluid outlet capacity of a pump. A pump with the novel control device has a housing means provided with an inlet and an outlet. Impeller means within the housing pumps fluid from the inlet to the outlet through a chamber means which is adjacent the impeller means. A feed back means is located adjacent the impeller means and communicates with the chamber means, while a flow control means controls the fluid flow in the feed back means. A means for varying the flow control means is provided and is connected to the housing,

For a better understanding of the present invention reference should be had to the accompanying drawings wherein like numerals of reference indicate similar parts throughout the several views and wherein:

FIGURE 1 is a vertical sectional view, partially cut away of a common pump arrangement embodying the control device of the present invention.

FIGURE 2 is an enlarged fragmentary vertical cross sectional view of the control device of the present invention and the adjacent chambers.

FIGURE 3 is a view similar to that shown in FIGURE 2 and showing fluid flow in the control device and adjacent chambers, and

FIGURE 4 is an alternative embodiment of the control device of the present invention.

Although the principles of the present invention are readily applicable to controlling a flow of fluid, the pres ent invention is particularly adapted for use in conjunction with pump arrangements and hence it has been so illustrated and will be so described.

With specific reference to the form of the present invention illustrated in the drawings, and referring partic ularly to FIGURE 1 a pump is generally indicated by the reference numeral 10.

In order to admit fluid into the pump 10, a pump housing 25 is provided to define an impeller or pump chamber 32 with a central inlet 12. Walls 14 of the inlet 12 define an inlet passage 16 which serves to direct incoming fluid toward the eye of a centrifugal impeller means or impeller 18. The impeller means 18 has a hub 20 which is connected to a shaft 22 by means of a screw arrangement 21 which holds the hub 20 in place on shaft 22. The impeller means 18 is constructed, shaped and spaced so that a clearance is available or defined in chamber 32 between the impeller means 18 and housing 25 forming a clearance space 24 between the eye of impeller means 18 and the adjacent walls 14 of the inlet pa sage 16; the clearance 24 around the impeller eye normally being restricted or blocked as much as possible by wear rings or running seals in the usual centrifugal pump.

structurally the impeller means 18 is provided with a particular shape (as seen in FIGURE 2), having a shroud 27 covering or defining the front of a bladed impeller passage 28 therein which receives fluid, such as a pulp carrying fluid, from the inlet passage 16. It is clear that when the fluid enters the inlet 12 and proceeds through the inlet passage 16, it is impelled outwardly by the action of the impeller means 18 through impeller passage 28 to the impeller periphery.

The means (not shown) for rotating the shaft 22 may be a device, such as a motor or any prime mover, well known to those skilled in the art.

With this arrangement of elements a suction or inlet pressure P-l (FIG. 3) is obtained in the inlet passage 16 and a pump or discharge pressure P-2 is created in the end impeller passage 28 at the periphery of impeller 18 by the centrifugal action which is well known to those skilled in the art. This pressure P-2 is normally maintained by the pump 10 when driven at a constant speed by the prime mover (not shown). However, it is often desirable to be able to vary the capacity of the pump 10 without varying its speed or the speed of the primemover by means of a control device. This invention is directed to such a control device.

Control device In order to vary the output capacity of the pump 10 without changing its speed or the speed of its prime-mover (not shown), an outer feed back passage means or feed back passage 30 (FIGS. 2, 3) is provided by the clearance between the housing 25 and the shroud 27 of the impeller means 18, which communicates with the discharge end impeller passage 28 in the periphery of impeller means 18 and the adjacent portion of the chamber means or impeller chamber 32 defined by the housing 25. This impeller chamber 32 adjacent the periphery of impeller 18 is provided to accept fluid pumped from the inlet 12 through the inlet passage 16 and the impeller passage 28 in the impeller means 18 before directing the fluid to the outlet 34.

A portion of the pumped fluid, which flows as indicated by the arrows shown in FIGURE 3, enters the impeller chamber 32 and may feed back into the formed feed back passage 30. If the outer feed back passage 30 is not obstructed, the fluid therein may further be fed back to the inlet eye or the rotating impeller means 18 through an inner feed back passage 36, which communicates through a control chamber 38 with the outer feed back passage 30; both passage 36 and chamber 38 also being defined by the housing 25 and the front shroud 27. The amount of fluid flow which is fed back through the passages 30 and 36, control chamber 38 and clearance 24 is controlled by a flow control means, such as an annular tire-like or tubular diaphragm 40 fixed to housing 25, which may be inflated or deflated thereby varying the size of the opening or flow area of the control chamber 38. The capacity of the pump therefore may be a function of the ability of the fluid in impeller chamber 32 to flow through the control chamber 38 back to the inlet eye of impeller means 18 by means of inner feed back passage 36. The tire-like diaphragm 40 disposed in the control chamber 38 when fully inflated will substantially block all flow of fluid fed back from the impeller chamber 32, thereby allowing the pump 10 to deliver maximum flow capacity to the outlet 34 (FIG- URE 3).

In order to vary the flow capacity of feed back in impeller chamber 32, the tire-like diaphragm 40 may be inflated or deflated thereby varying the size or area of the control chamber 38 and consequently varying the amount of fluid being fed back. In this manner the output capacity of impeller chamber 32 or pump 10 is varied.

In order to inflate or deflate the tire-like diaphragm 40, such diaphragm 40 is provided with an inlet portion 42 disposed in a passage 43 in the housing 25, and connected to fluid supply means (not shown) but indicated by the legend Fluid Supply Means. The amount of fluid (such as air or liquid) passing to the diaphragm 40 is controlled by a device, such as a valve 45, well known to those skilled in the art for controlling the flow of fluid through a particular point. It will be understood by those skilled in the art that the above described control device may have other forms and embodiments.

Alternative embodiment Alternatively, as shown in FIGURE 4, a method may be provided for feeding fluid from the impeller chamber 32 back through a conduit 44 with a valve 46 disposed therein for controlling the amount of fluid being fed to the tire-like diaphragm 40. In this manner an outside source of fluid for inflating the diaphragm 40 is not required and provides a further measure of control on the output capacity of the pump 10.

It will be recognized by those skilled in the art that the objects of the present invention have been achieved by providing a novel control device in which the output flow capacity of a pump may be varied by varying the size of a bypass or a bleed-off means thereby taking away some of the flow which is being developed in the impeller chamber 32 before delivering the flow to the outlet. This control device eliminates varying the speed of the prime mover, eliminates mechanical linkages and gears and further provides an economical and durable method of varying the output of the pump.

While in accordance with the patent statutes a preferred embodiment of the present invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

I claim:

1. A variable capacity centrifugal pump comprising:

(a) a housing defining a chamber having an outlet and a front wall with a central chamber inlet therethrough; Y

(b) impeller means rotatably disposed in the chamber and spaced from the front wall to define therebetween an annular feed back passage for fluid being pumped to the central inlet; and

(c) flexible annular means disposed in the feed back passage being variable in response to pressure fluid for controlling flow of fluid being pumped therethrough to vary the flow of fluid being pumped through the outlet;

(d) the annular means having an inlet adapted to receive pressure fluid for varying such annular means.

2. A variable capacity centrifugal pump in accordance with claim 1, and:

(a) the inlet of the annular means having valve means for controlling the flow of pressure fluid therethrough.

3. A variable capacity centrifugal pump in accordance with claim 2, wherein:

(a) the valve means communicates with the outer periphery to provide a controlled flow of pumped fluid as pressure fluid for varying the annular means.

4. A variable capacity centrifugal pump comprising:

(a) a housing defining a chamber having an outlet and a front wall with a central chamber inlet therethrough;

(b) a centrifugal impeller rotatably disposed in the chamber having an inlet eye to receive fluid to be pumped and a peripheral outlet for pumped fluid in communication with the periphery of the chamber;

(0) the centrifugal impeller being spaced from the front wall to define an annular feed back passage therebetween in the chamber; and

(d) an annular flexible diaphragm disposed in the passage, fixed to the front wall, and extensible in response to pressure fluid to restrict the annular passage for controlling flow therethrough to control the flow of pumped fluid through the outlet;

(e) the diaphragm having an inlet adapted to receive pressure for extension thereof.

5. A variable capacity centrifugal pump in accordance with claim 4, and:

(a) the inlet of the annular means having valve means for controlling the flow of pressure fluid there through.

6. A variable capacity centrifugal pump in accordance with claim 5, wherein:

(a) the valve means communicates with the outer periphery to provide a controlled flow of pumped fluid as pressure fluid for extension of the diaphragm.

7. A variable capacity centrifugal pump comprising:

(a) a housing defining a chamber having an outlet and a front wall with a central chamber inlet therethrough;

(b) a centrifugal impeller rotatably disposed in the chamber having an inlet eye to receive fluid to be pumped and a peripheral outlet for pumped fluid in communication with the periphery of the chamber;

(0) the centrifugal impeller being spaced from the front wall to define an annular feed back passage therebetween in the chamber; and

(d) an annular tubular diaphragm disposed in the passage, fixed to the front wall, and inflatable in response to pressure fluid to restrict the annular 5 passage for controlling flow therethrough to control the flow of pumped fluid through the outlet;

(e) the diaphragm having an inlet adapted to receive pressure for inflation thereof.

8. A variable capacity centrifugal pump in accordance with claim 7, and:

(a) the inlet of the annular means having valve means for controlling the flow of pressure fluid therethrough.

9. A variable capacity centrifugal pump in accordance with claim 8 wherein:

(a) the valve means communicates with the outer periphery to provide a controlled flow of pumped fluid as pressure fluid for inflating the tubular diaphragm.

References Cited by the Examiner UNITED STATES PATENTS 1,428,238 9/22 Keating 103102 2/ 24 Sessions 103-111 5/49 Loss 230-115 l/55 Newcomb 230114 6/56 Fletcher 103--111 3 5 7 Kenney l0397 12/5 8 Cliborn 103-97 2/ 5 9 Forrest l0397 4/60 Court 230-114 11/60 Forshaw 230-114 FOREIGN PATENTS 9/ 41 Germany. 3/54 Germany. 10/55 Switzerland.

LAURENCE V. EFNER, Primary Examiner. 

1. A VARIABLE CAPACITY CENTRIFUGAL PUMP COMPRISING: (A) A HOUSING DEFINING A CHAMBER HAVING AN OUTLET AND A FRONT WALL A CENTRAL CHAMNER INLET THERETHROUGH; (B) IMPELLER MEANS ROTATABLY DISPOSED IN THE CHAMBER AND SPACED FROM THE FRONT WALL TO DEFINE THEREBETWEEN AN ANNULAR FEED BACK PASSAGE FOR FLUID BEING PUMPED TO THE CENTRAL INLET; AND (C) FLEXIBLE ANNULAR MEANS DISPOSED IN THE FEED BACK PASSAGE BEING VARIABLE IN RESPONSE TO PRESSURE FLUID FOR CONTROLLING FLOW OF FLUID BEING PUMPED THERETHROUGH TO VARY THE FLOW OF FLUID BEING PUMPED THROUGH THE OUTLET; (D) THE ANNULAR MEANS HAVING AN INLET ADAPTED TO RECEIVE PRESSURE FLUID FOR VARYING SUCH ANNULAR MEANS. 